1. Field of the Invention
This invention relates to a novel basic cross-linked copolymer having substituted aminoethyl groups and a process for the production thereof.
2. Description of the Prior Art
Various cross-linked copolymers having substituted aminomethyl groups are known. Of these cross-linked copolymers, weakly basic anion ion-exchange resins having dialkylaminomethyl groups and strongly basic anion ion-exchange resins having trialkylammonium methyl groups (R.sub.1 R.sub.2 R.sub.3 N.sup..sym. CH.sub.2 --:R.sub.1, R.sub.2, R.sub.3, each being an alkyl group) are representative ones and it might be said that almost all the commercially available anion exchange resins are of these types. The conventionally known representative method of preparing these resins comprises reacting a starting polymer such as a divinylbenzene-styrene copolymer with chloromethyl methyl ether in the presence of a Friedel-Crafts catalyst to produce a chloromethylated polymer and aminating the chloromethylated polymer with a dialkylamine or a trialkylamine. However, according to this method, cross-linking reaction often occurs as a side reaction in the chloromethylation to disadvantageously increase the degree of cross-linking and to reduce the exchange capacity. With high degrees of cross-linking the subsequent amination does not complete. Furthermore, the harm of haloalkyl ethers such as chloromethyl methyl ether is recently at issue.